1. Field of the Invention
The invention relates to implant devices and instruments used to repair body tissue. In particular, the invention relates to a implant devices, instruments and methods for repairing body tissue during endoscopic surgical procedures. Still more particularly, the invention relates to implant devices, instruments and methods for repairing meniscal tissue during arthroscopic surgery of the knee.
2. Description of the Prior Art
Implant devices for repairing body tissue are known in the prior art. While such devices may be classified into several categories, the present invention is related to instruments and methods for inserting into a site of implantation elongated devices having transversely extending barbs or projections which assist in retaining the implant in place within a tissue defect (e.g. a tear) to hold body tissue in close approximation for healing or other reasons.
One such known device is described in U.S. Pat. No. 4,873,976 (Schrieber). This device comprises a solid elongated shaft having a plurality of transversely extending projections, a pointed tip and a transverse circular head at its proximal end. The Schrieber device is inserted at a surgical site of implantation by being pushed through an elongated hollow tube which is held next to, but does not itself penetrate the site of implantation.
Other similar devices are disclosed in U.S. Pat. Nos. 4,884,572; 4,895,148; 4,924,865; and 4,976,715 all issued to Bays et al. The devices disclosed in these Bays et al. patents primarily differ from the Schrieber device in that they are cannulated. The Bays et al. patents are assigned to the assignee hereof and, along with the Schrieber patent, are incorporated by reference herein. The Bays et al. device is inserted at a surgical site of implantation with an applicator having a needle passing through an axial bore of the applicator and through an axial bore of the implant. The implant is held at the tip of the applicator and inserted into the site of implantation directly through a portal or through an insertion cannula. The needle protrudes distally from the implant and both the needle and implant are pushed into the tissue while so assembled. The needle is then disassembled from the applicator and removed.
All of the above described elongated devices are arrow-like and are designed to be inserted or pushed into tissue to be repaired. The devices are sometimes referred to as "tissue anchors" because they hold tissue together during healing. While these devices are intended to be used during arthroscopic, or more generally endoscopic procedures, that very fact makes the insertion sometimes difficult. As described above, it is known to use elongated cannulas to guide the implants into position and smaller push rods to push them in. Insertion devices and methods used with the Schrieber type non-cannulated device require the implant to be pushed through a cannula with an elongated pusher sized to be slidingly received within the cannula. Insertion devices and methods used with cannulated devices such as those disclosed in the Bays et al. patents require the implant device to be secured to the distal tip of a holding device and pushed into place, with or without the use of a guiding cannula. An improved cannulated implant and insertion system have been recently developed and are described in pending U.S. patent application Ser. No. 09/141,175 entitled Cannulated Tissue Anchor System, assigned to the assignee hereof and incorporated by reference herein. The insertion system shown in this application comprises a housing, an elongated tubular shaft extending distally from the housing, the shaft having an axially aligned bore therethrough and an elongated needle adapted to be slidably received within the bore of the shaft. The shaft is adapted to receive a cannulated tissue anchor while the needle is adapted to be received in the bore of the anchor. A trigger means is provided on the housing for moving the distal end of the needle between a first, retracted position, in which the needle is maintained within the shaft bore, and a second, extended position, in which the needle is extended distally, beyond the shaft bore. A push rod for pushing the anchor out of the device is adapted to be slidably received within the shaft bore and moved between a first, retracted position, in which the distal end of the push rod is maintained within the shaft bore, and a second, extended position, in which the distal end of the push rod is adjacent or slightly beyond the distal end of the shaft.
It is always desirable to simplify the insertion process for push-in, arrow-like implant devices. Accordingly, it is an object of this invention to develop a tissue repair system incorporating a cannulated push-in implant or tissue anchor device, preferably bioabsorbable, and a simplified insertion apparatus, preferably operable by one hand.
It is also generally an object of this invention to provide a tissue anchor inserting device and method for guiding and inserting a cannulated tissue anchor into position at a surgical site.
It is another object of this invention to provide an elongated inserting device for receiving therein a cannulated tissue anchor, preferably at its distal end.
It is still another object of this invention to provide an elongated inserting device suitable for endoscopic procedures and capable of being operated from its proximal end.
It is also an object of this invention to provide a tissue anchor inserting system which facilitates the assembly of an inserting device with a cannulated tissue anchor.
It is yet another object of this invention to provide a system incorporating a single use subassembly for retaining a tissue anchor and associated insertion components and a reusable activating instrument for receiving the subassembly and inserting the tissue anchor into place at a site of implantation.
It is an additional object of this invention to provide a reusable activating instrument having selectively interchangeable cartridges design to adapt the instrument for use with different size tissue anchors.